[In vivo antiplasmodial activity of Mycale laxissima and Clathria echinata sponges]. / Actividad antiplasmodial in vivo de las esponjas Mycale laxissima y Clathria echinata.

INTRODUCTION: the search of new antimalarial compounds comprises, among its challenges, the development of therapeutic alternatives for cerebral malaria; due to the high mortality and neurological deficiencies that persist after treatment with recommended drugs. OBJECTIVES: to evaluate the activity of organic fractions of Mycale laxissima and Clathria echinata in the cerebral malaria model of infection of C57BL/6 mice with Plasmodium berghei ANKA. METHODS: preparative fractions of both species were obtained by reverse-phase flash chromatography. In order to detect the presence of saponins, triterpenods/steroids and alkaloids, a qualitative chemical analysis was performed. The schyzontocidal effect of the extracts was determined by the suppression test at the beginning of the infection. Survival, neurological symptoms and body weight changes were evaluated in subsequent days. RESULTS: the organic fractions of Mycale laxissima at 200 mg/kg and Clathria echinata at 100 mg/kg showed neither substantial reductions of body weights, nor deaths of animals until day 4; but caused significant reductions of median parasitemia of 45 % and 53 % respectively. The fraction of Mycale laxissima at 200 mg/kg caused a significant increase in the median survival time up to day 20, whereas animals treated with Clathria echinata at 100 mg/kg presented a survival of 16 days. Both increases the survival time 7 days. Neurological alterations were not observed in the groups treated with organic fractions when compared to the control group. This survival extension was similar to the effect of administration of 7.5 mg/kg of chloroquine. CONCLUSIONS: the organic fractions of Mycale laxissima and Clathria echinata exhibited promising antimalarial activities in the infection model of C57BL/6 mice with Plasmodium berghei ANKA. This indicates that their active chemical constituents should be studied.

[Increase of analytical sensitivity of FasciDIG system for the diagnosis of Fasciola hepatica]. / Incremento de la sensibilidad analítica del sistema FasciDIG para el diagnóstico de Fasciola hepatica.

INTRODUCTION: fasciolosis is an endemic disease in cattle in Cuba and there is an increase in the number of reported human cases in recent years. The coproparasitological diagnosis of fasciolosis has low sensitivity and is hard-working; for that reason, it is important to use immunoenzymatic methods mainly those that can detect this parasite antigens in the feces. A system for antigen detection called FasciDIG, with a reported sensitivity of 10 ng/mL has been developed in "Pedro Kouri" Institute of Tropical Medicine. OBJECTIVE: to increase the sensitivity of FasciDIG through some modifications to this diagnostic method. METHODS: two foul dilutions (concentrations of antigen 1 000 ng/mL- 1.95ng/mL in H20 Tween-20) were evaluated in a simulated system using FasciDIG and modified FasciDIG. The FasciDiG was modified using the secondary antibody obtained from rabbit against excretory-secretory antigens of Fasciola hepatica combined with biotin and then adding commercial conjugated extravidine peroxidase. Feces were collected from the rectum of 96 animals for slaughter and were evaluated by both methods, FasciDig and modified FasciDig. Kappa index was calculated between both assays. RESULTS: the detection limit for the FasciDIG was 3.9 ng/mL whereas the modified FasciDIG detected up to 1.95 ng/mL. The agreement index calculated between the two tests was 0.6238 corresponding to an index of substantive or good agreement. CONCLUSIONS: the modified method is more sensitive than FasciDIG and it can supplement the diagnosis of fasciolosis. The number of analyzed samples should be increased and the sensitivity and specificity should also be determined using the serial conic-cup sedimentation technique as the gold standard.